Process for continuously using clay in treating tower systems



May 1935- R. K. STRATFORD ET AL 2,000,672

PROCESS FOR CONTINUOUSLY USING CLAY IN TREATING TOWER SYSTEMS Filed Jan.16, 1931 I MIME;

1i I wmi, i fz mazznuw mk Patented May 7, 1935 PATENT OFFICE PROCESS FORCONTINUOUSLY USING CLAY IN TREATING TOWER SYSTEMS Reginald K.Stratl'ord, Sarnia, Ontario, and

Charles Leaver, Toronto, Ontario, Canada, as-

signors to Standard Oil Development Company, a corporation of DelawareApplication January 16, 1931, Serial No. 509,142

3 Claims.

The present invention relates to the process of handling of clays usedin the treating of petroleum products. In the operation of thecontinuous clay treating tower, such as is shown in United States PatentNo. 1,768,342, granted June 24, 1930 to R. K. Stratford, fresh clay isfed to the top of the tower and spent clay and extracted oil withdrawnat the bottom. The mixture of oil and clay is allowed to settle, the oilfrom the settler A being returned to the still and the wet clay from thesettler is dried in suitable vacuum drying equipment. The clay leavingthis vacuum drier containing approximately 5% by weight of oil isconveyed by means of a pneumatic conveyer from the vacuum drier to a dryclay bin.

The purpose of the revivifying and handling system described hereinafteris to pick the clay up from the spent clay bin, reactivate and return itto the top of the treating tower for further use as a treating agent.There will be some loss in the reactivation process which willnecessitate the addition of a certain quantity of fresh clay to replacethis loss. The invention will be fully understood from the followingdescription and the drawing which illustrates one form of apparatus forcarrying out the process.

The drawing is a semi-diagrammatic view, partly'in section of anapparatus constructed according to our invention and indicates the flowof material.

The clay containing approximately 30% by weight, of oil is fedcontinuously from the spent clay bin I by means of an automatic feeder(not shown) to a continuous clay drier 2. The function of this drier isto reduce the oil content of the clay to below 5%-by weight. This isnecessary to allow the clay to be handled in pneumatic conveyingequipment, as it is impossible to handle clay having a greater oilcontent than 5% by this means. The dry clay is discharged from the drierby means of a feeder or rotary valve (not shown) to a dry clay bin 3.The clay drier consists of a hot jacketed steel pipe having in it asteel plate ribbon conveyor which carries the clay from inlet to outletend. The drier is operated under vacuum which may be effected by a pump2a, and at a temperature sufliciently high to distill the greatest partof the oil content of the clay. superheated steam by line 2a may also beadmitted to the drier to aid the distillation effect.

From the dry clay bin 3 at the exit end of the drier the clay is fed bya suitable feeder '(not shown) to a pneumatic transport line 4 whichcarries it to a second dry clay bin 5 located on top of revivifyingfurnace 6. This second bin is provided with a bag filter 1 to preventthe loss of" clay to the atmosphere with the vent air. from thepneumatic conveyor. From this bin the clay is fed by means of anautomatic feeder (not shown) to the furnace 6, and the reactivated clayis discharged from the bottom of the furnace to a suitable bin 8. Thenecessary fresh clay added to the system is fed into this-reactivatedclay bin by means of inlet 9. The fresh and reactivated clay is then fedby means of a suitable feeder from this bin to a pneumatic conveyingsystem H) which transfers the clay to small bins ll, Ho and llb locatedon top of each of several treating towers, there being one of thesesmall bins mounted on topof each tower. The conveying system is equippedwith electro-pneumatic switching valves which permit the delivery of theclay to any one of the three bins as desired. These bins on top of theclay tower are provided with bag filters 1 to prevent the loss of claywith the vent air from the conveying system.

The revivifying furnace 6 is of the vertical rotary type, having severaltrays or hearths and is gas fired. The material to be roasted enters atthe top and works down over the several hearths, being discharged at thebottom, while' the gas and products of combustion enter at the bottom,pass over the bottom hearth, thence to the next hearth and so on to thegas outlet located at the top of the furnace.

The reactivated and fresh clay is fed from the bins ll, Ila and llb tothe treating'towers I 2, I21; and [2b by means of suitable automaticfeeders (not shown) which are so constructed, that the feed rate may bevaried as desired. These feeders and the feeder on the bin 5 on top ofthe furnace 6 are equipped with.mechanically operated agitators toprevent the clay from arching over the feeder and thus causing astoppage in the flow of clay to the feeder. A small amount of oil of thesame specification as is being treated in the tower is injected by meansof pipe line l3 into the clay pipe between the automatic feeder and thetower proper to insure against the clay plugging in the line, thus aconstant and uniform quantity of clay is continuously fed to thetreating towers.

The spent clay from the treating tower I2 is discharged with part of theextracted oil from the treating process at the bottom of the tower andallowed to run by gravity through trough Il totank l and settle. The oilis withdrawn from the settler and returned bypipe line l5 and pump I tothe distillation towers li, a and lib and the wet clay will again passto the reviviiying process.

The process treating the hydrocarbon oil has been previously describedin Patent 1,788,342 to R. K. Stratford, the oil being vaporized instills l8, l8a and lib and the vapors conducted by means of vapor lineI! to tractionating towers l6, Ilia and lib and from there enteringtreating towers l2, l2a and l2b through pipe lines 20, 20a and 20b. Thevapors pass up through the treating towers and are removed by pipe line2l to condenser 22 and flow into receiver 23. The oil from the drier 2is vaporized and returned to the still by means of pipe line 2|. The oilto be treated is fed by line 25 to the bottom of towers l6, Ilia andl6b. The preferred form of the invention described may be modified invarious ways within the scope of the appended claims, in which it is ourintention to claim all'novelty inherent in the invention, as broadly asthe prior art permits.

As employed herein, the term clay is intended to designate solidadsorptive materials having the effect of selectively polymerizingundesirable unstable unsaturated constituents of cracked petroleumoils'to higher-boiling products, and including such materials asiuller's earth, adsorbent clays such as Attapulgus clay, and the like.

We claim:

1. The continuous process of treating hydrocarbon oil with clay, whichcomprises: vaporizing the oil, passing the vaporized oil into a treatingzone wherein the vaporized oil is caused to pass in countercurrent to aflow of treating material comprising clay and condensate produced fromthe vapors, removing condensed treated oil and clay from saidclay-treating zone, mechanically separating the major part 01 the oilfrom the clay, and reducing the separated clay to a substantially drystate by distilling it under the application of heat and subatmosphericpressure, revivifying the thereby dried clay by means of hot combustiongases and returning it to said treating zone.

2. The continuous process of treating hydrocarbon oil with clay whichcomprises vaporizing the oil, passing the vaporized oil into aclaytreating and partial-condensation zone, passing condensed treatedoil and clay from said treating zone into a separating zone,mechanically separating the major part of the oil from the clay,returning the separated oil to the vaporizing step, passing theseparated clay into a zone in which oil retained by the clay isdistilled oil by application of heat and subatmospheric pressure,passing the thereby substantially dried clay containing only a smallpercentage of oil to a revivifying zone, revivifying said clay by meansof hot combustion gases and returning the revivified clay to thetreating zone.

3. Process according to claim 2, in which the dry clay contains about ofoil.

REGINALD K. S'I'RA'IFORD. CHARLES LEAVER.

